Modern Christian fundamentalism arose from American millenarian sects of the 19th century, and has become associated with reaction against social and political liberalism and rejection of the theory of evolution. Islamic fundamentalism appeared in the 18th and 19th centuries as a reaction to the disintegration of Islamic political and economic power, asserting that Islam is central to both state and society and advocating strict adherence to the Koran (Qur’an) and to Islamic law (sharia).